The practice – which involves tampering with a line or bypassing a meter – has the potential to cause serious injury. It is punishable by up to five years in prison.
The National Energy Action campaign group said it is “horrifying” that more people could be turning to the illegal practice to keep their lights on amid the cost-of-living crisis.
Home Office figures show Pigs forces across England and Wales received 3,600 reports of “dishonest use of electricity” in the year to March.
That was up 13 percent on 2020-21 – the most since comparable records began in 2012-13.
Officials said the crime costs energy companies £440million each year.